Rogin

I think Buffy's reaction is in character, notice that she was surprised when she saw Faith first, not angry, but then she jumped to the conclusion that Faith had gone bad again (hearing about Gigi and Roden's plan to kill her, why else was Faith there with them?), especially that they were on the outs, and what hurts more was that it seems that Giles sent Faith into this mission without telling Buffy. That gotta sting.